Comment by hackyhacky

> Calling someone a liar is not an argument.

Correct. On its own, calling someone a liar is not an argument. However, if a person is a liar, that fact provides useful context in evaluating statements made by that person. Traditionally, when a person has been shown to lie repeatedly, one should expect them to continue lying, and therefore one should not take their statements at face value. Can you understand how that is relevant in this case?